Background: This study aimed to verify the influence of COVID-19-induced depression on smartphone usage time among multicultural adolescents, as well as the moderated mediation effect of gender through anxiety.Methods: Using the raw data from the 2021 Korea Youth Risk Behavior Survey, a sample of 1,161 multicultural adolescents was recruited for this study. Models 4 and 7 of the PROCESS macro method were used for data analysis.Results: COVID-19-induced depression among multicultural adolescents positively influenced their smartphone usage time. Moreover, their anxiety fully mediated the influence of COVID-19-induced depression on their smartphone usage time. The mediation effect of COVID-19-induced depression on smartphone usage time through anxiety was moderated by their gender.Conclusions: The results are significant in that they provide insights for addressing the problem of smartphone usage among multicultural adolescents amid a disaster like COVID-19.